150 



THE APPLE 



of the requirements of the fruit trees. In Wyoming the duty of 

 water is seldom less than i cubic foot per second for yo acres. In 

 parts of southern California the same quantity of water not infre- 

 quently serves 400 acres ; yet the amount required by the fruit 

 trees of the latter locality is far in excess of that of the former. 

 In recent years the tendency throughout the West has been 

 toward a more economical use of water, and even in localities 



Fig. 71. Duty of water 



Average duty per month under Riverside Water Company, December i, 1901, to 

 November 30, 1908 



where water for irrigation is still reasonably low in price, it is 

 rare that more than 2\ acre-feet per acre is applied in a season. 

 This is the duty provided for in the contracts of the Bitter Root 

 Valley Irrigation Company of Montana, which has 40,000 acres 

 of fruit lands under ditch. Since, however, the water user is not 

 entitled to receive more than \ acre-foot per acre in any one 

 calendar month, it is only when the growing season is long and 

 dry that he requires the full amount. 



In the vicinity of Boulder, Colorado, the continuous flow of 

 1 cubic foot per second for 105 days serves about 112 acres of 



